// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.

#include "ui/views/view.h"

#include <algorithm>
#include <cmath>
#include <utility>

#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/stl_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "third_party/skia/include/core/SkRect.h"
#include "ui/accessibility/ax_enums.h"
#include "ui/base/cursor/cursor.h"
#include "ui/base/dragdrop/drag_drop_types.h"
#include "ui/base/ime/input_method.h"
#include "ui/compositor/clip_recorder.h"
#include "ui/compositor/compositor.h"
#include "ui/compositor/dip_util.h"
#include "ui/compositor/layer.h"
#include "ui/compositor/layer_animator.h"
#include "ui/compositor/paint_context.h"
#include "ui/compositor/paint_recorder.h"
#include "ui/compositor/transform_recorder.h"
#include "ui/events/event_target_iterator.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/geometry/point3_f.h"
#include "ui/gfx/geometry/point_conversions.h"
#include "ui/gfx/interpolated_transform.h"
#include "ui/gfx/path.h"
#include "ui/gfx/scoped_canvas.h"
#include "ui/gfx/screen.h"
#include "ui/gfx/skia_util.h"
#include "ui/gfx/transform.h"
#include "ui/native_theme/native_theme.h"
#include "ui/views/accessibility/native_view_accessibility.h"
#include "ui/views/background.h"
#include "ui/views/border.h"
#include "ui/views/context_menu_controller.h"
#include "ui/views/drag_controller.h"
#include "ui/views/focus/view_storage.h"
#include "ui/views/layout/layout_manager.h"
#include "ui/views/views_delegate.h"
#include "ui/views/widget/native_widget_private.h"
#include "ui/views/widget/root_view.h"
#include "ui/views/widget/tooltip_manager.h"
#include "ui/views/widget/widget.h"

#if defined(OS_WIN)
#include "base/win/scoped_gdi_object.h"
#include "ui/native_theme/native_theme_win.h"
#endif

namespace views {

namespace {

#if defined(OS_WIN)
    const bool kContextMenuOnMousePress = false;
#else
    const bool kContextMenuOnMousePress = true;
#endif

    // Default horizontal drag threshold in pixels.
    // Same as what gtk uses.
    const int kDefaultHorizontalDragThreshold = 8;

    // Default vertical drag threshold in pixels.
    // Same as what gtk uses.
    const int kDefaultVerticalDragThreshold = 8;

    // Returns the top view in |view|'s hierarchy.
    const View* GetHierarchyRoot(const View* view)
    {
        const View* root = view;
        while (root && root->parent())
            root = root->parent();
        return root;
    }

} // namespace

// static
const char View::kViewClassName[] = "View";

////////////////////////////////////////////////////////////////////////////////
// View, public:

// Creation and lifetime -------------------------------------------------------

View::View()
    : owned_by_client_(false)
    , id_(0)
    , group_(-1)
    , parent_(NULL)
    , visible_(true)
    , enabled_(true)
    , notify_enter_exit_on_child_(false)
    , registered_for_visible_bounds_notification_(false)
    , clip_insets_(0, 0, 0, 0)
    , needs_layout_(true)
    , snap_layer_to_pixel_boundary_(false)
    , flip_canvas_on_paint_for_rtl_ui_(false)
    , paint_to_layer_(false)
    , accelerator_focus_manager_(NULL)
    , registered_accelerator_count_(0)
    , next_focusable_view_(NULL)
    , previous_focusable_view_(NULL)
    , focusable_(false)
    , accessibility_focusable_(false)
    , context_menu_controller_(NULL)
    , drag_controller_(NULL)
    , native_view_accessibility_(NULL)
{
    SetTargetHandler(this);
}

View::~View()
{
    if (parent_)
        parent_->RemoveChildView(this);

    ViewStorage::GetInstance()->ViewRemoved(this);

    for (Views::const_iterator i(children_.begin()); i != children_.end(); ++i) {
        (*i)->parent_ = NULL;
        if (!(*i)->owned_by_client_)
            delete *i;
    }

    // Release ownership of the native accessibility object, but it's
    // reference-counted on some platforms, so it may not be deleted right away.
    if (native_view_accessibility_)
        native_view_accessibility_->Destroy();
}

// Tree operations -------------------------------------------------------------

const Widget* View::GetWidget() const
{
    // The root view holds a reference to this view hierarchy's Widget.
    return parent_ ? parent_->GetWidget() : NULL;
}

Widget* View::GetWidget()
{
    return const_cast<Widget*>(const_cast<const View*>(this)->GetWidget());
}

void View::AddChildView(View* view)
{
    if (view->parent_ == this)
        return;
    AddChildViewAt(view, child_count());
}

void View::AddChildViewAt(View* view, int index)
{
    CHECK_NE(view, this) << "You cannot add a view as its own child";
    DCHECK_GE(index, 0);
    DCHECK_LE(index, child_count());

    // If |view| has a parent, remove it from its parent.
    View* parent = view->parent_;
    ui::NativeTheme* old_theme = NULL;
    if (parent) {
        old_theme = view->GetNativeTheme();
        if (parent == this) {
            ReorderChildView(view, index);
            return;
        }
        parent->DoRemoveChildView(view, true, true, false, this);
    }

    // Sets the prev/next focus views.
    InitFocusSiblings(view, index);

    // Let's insert the view.
    view->parent_ = this;
    children_.insert(children_.begin() + index, view);

    views::Widget* widget = GetWidget();
    if (widget) {
        const ui::NativeTheme* new_theme = view->GetNativeTheme();
        if (new_theme != old_theme)
            view->PropagateNativeThemeChanged(new_theme);
    }

    ViewHierarchyChangedDetails details(true, this, view, parent);

    for (View* v = this; v; v = v->parent_)
        v->ViewHierarchyChangedImpl(false, details);

    view->PropagateAddNotifications(details);
    UpdateTooltip();
    if (widget) {
        RegisterChildrenForVisibleBoundsNotification(view);
        if (view->visible())
            view->SchedulePaint();
    }

    if (layout_manager_.get())
        layout_manager_->ViewAdded(this, view);

    ReorderLayers();

    // Make sure the visibility of the child layers are correct.
    // If any of the parent View is hidden, then the layers of the subtree
    // rooted at |this| should be hidden. Otherwise, all the child layers should
    // inherit the visibility of the owner View.
    UpdateLayerVisibility();
}

void View::ReorderChildView(View* view, int index)
{
    DCHECK_EQ(view->parent_, this);
    if (index < 0)
        index = child_count() - 1;
    else if (index >= child_count())
        return;
    if (children_[index] == view)
        return;

    const Views::iterator i(std::find(children_.begin(), children_.end(), view));
    DCHECK(i != children_.end());
    children_.erase(i);

    // Unlink the view first
    View* next_focusable = view->next_focusable_view_;
    View* prev_focusable = view->previous_focusable_view_;
    if (prev_focusable)
        prev_focusable->next_focusable_view_ = next_focusable;
    if (next_focusable)
        next_focusable->previous_focusable_view_ = prev_focusable;

    // Add it in the specified index now.
    InitFocusSiblings(view, index);
    children_.insert(children_.begin() + index, view);

    ReorderLayers();
}

void View::RemoveChildView(View* view)
{
    DoRemoveChildView(view, true, true, false, NULL);
}

void View::RemoveAllChildViews(bool delete_children)
{
    while (!children_.empty())
        DoRemoveChildView(children_.front(), false, false, delete_children, NULL);
    UpdateTooltip();
}

bool View::Contains(const View* view) const
{
    for (const View* v = view; v; v = v->parent_) {
        if (v == this)
            return true;
    }
    return false;
}

int View::GetIndexOf(const View* view) const
{
    Views::const_iterator i(std::find(children_.begin(), children_.end(), view));
    return i != children_.end() ? static_cast<int>(i - children_.begin()) : -1;
}

// Size and disposition --------------------------------------------------------

void View::SetBounds(int x, int y, int width, int height)
{
    SetBoundsRect(gfx::Rect(x, y, std::max(0, width), std::max(0, height)));
}

void View::SetBoundsRect(const gfx::Rect& bounds)
{
    if (bounds == bounds_) {
        if (needs_layout_) {
            needs_layout_ = false;
            Layout();
        }
        return;
    }

    if (visible_) {
        // Paint where the view is currently.
        SchedulePaintBoundsChanged(
            bounds_.size() == bounds.size() ? SCHEDULE_PAINT_SIZE_SAME : SCHEDULE_PAINT_SIZE_CHANGED);
    }

    gfx::Rect prev = bounds_;
    bounds_ = bounds;
    BoundsChanged(prev);
}

void View::SetSize(const gfx::Size& size)
{
    SetBounds(x(), y(), size.width(), size.height());
}

void View::SetPosition(const gfx::Point& position)
{
    SetBounds(position.x(), position.y(), width(), height());
}

void View::SetX(int x)
{
    SetBounds(x, y(), width(), height());
}

void View::SetY(int y)
{
    SetBounds(x(), y, width(), height());
}

gfx::Rect View::GetContentsBounds() const
{
    gfx::Rect contents_bounds(GetLocalBounds());
    if (border_.get())
        contents_bounds.Inset(border_->GetInsets());
    return contents_bounds;
}

gfx::Rect View::GetLocalBounds() const
{
    return gfx::Rect(size());
}

gfx::Rect View::GetLayerBoundsInPixel() const
{
    return layer()->GetTargetBounds();
}

gfx::Insets View::GetInsets() const
{
    return border_.get() ? border_->GetInsets() : gfx::Insets();
}

gfx::Rect View::GetVisibleBounds() const
{
    if (!IsDrawn())
        return gfx::Rect();
    gfx::Rect vis_bounds(GetLocalBounds());
    gfx::Rect ancestor_bounds;
    const View* view = this;
    gfx::Transform transform;

    while (view != NULL && !vis_bounds.IsEmpty()) {
        transform.ConcatTransform(view->GetTransform());
        gfx::Transform translation;
        translation.Translate(static_cast<float>(view->GetMirroredX()),
            static_cast<float>(view->y()));
        transform.ConcatTransform(translation);

        vis_bounds = view->ConvertRectToParent(vis_bounds);
        const View* ancestor = view->parent_;
        if (ancestor != NULL) {
            ancestor_bounds.SetRect(0, 0, ancestor->width(), ancestor->height());
            vis_bounds.Intersect(ancestor_bounds);
        } else if (!view->GetWidget()) {
            // If the view has no Widget, we're not visible. Return an empty rect.
            return gfx::Rect();
        }
        view = ancestor;
    }
    if (vis_bounds.IsEmpty())
        return vis_bounds;
    // Convert back to this views coordinate system.
    gfx::RectF views_vis_bounds(vis_bounds);
    transform.TransformRectReverse(&views_vis_bounds);
    // Partially visible pixels should be considered visible.
    return gfx::ToEnclosingRect(views_vis_bounds);
}

gfx::Rect View::GetBoundsInScreen() const
{
    gfx::Point origin;
    View::ConvertPointToScreen(this, &origin);
    return gfx::Rect(origin, size());
}

gfx::Size View::GetPreferredSize() const
{
    if (layout_manager_.get())
        return layout_manager_->GetPreferredSize(this);
    return gfx::Size();
}

int View::GetBaseline() const
{
    return -1;
}

void View::SizeToPreferredSize()
{
    gfx::Size prefsize = GetPreferredSize();
    if ((prefsize.width() != width()) || (prefsize.height() != height()))
        SetBounds(x(), y(), prefsize.width(), prefsize.height());
}

gfx::Size View::GetMinimumSize() const
{
    return GetPreferredSize();
}

gfx::Size View::GetMaximumSize() const
{
    return gfx::Size();
}

int View::GetHeightForWidth(int w) const
{
    if (layout_manager_.get())
        return layout_manager_->GetPreferredHeightForWidth(this, w);
    return GetPreferredSize().height();
}

void View::SetVisible(bool visible)
{
    if (visible != visible_) {
        // If the View is currently visible, schedule paint to refresh parent.
        // TODO(beng): not sure we should be doing this if we have a layer.
        if (visible_)
            SchedulePaint();

        visible_ = visible;
        AdvanceFocusIfNecessary();

        // Notify the parent.
        if (parent_) {
            parent_->ChildVisibilityChanged(this);
            parent_->NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, false);
        }

        // This notifies all sub-views recursively.
        PropagateVisibilityNotifications(this, visible_);
        UpdateLayerVisibility();

        // If we are newly visible, schedule paint.
        if (visible_)
            SchedulePaint();
    }
}

bool View::IsDrawn() const
{
    return visible_ && parent_ ? parent_->IsDrawn() : false;
}

void View::SetEnabled(bool enabled)
{
    if (enabled != enabled_) {
        enabled_ = enabled;
        AdvanceFocusIfNecessary();
        OnEnabledChanged();
    }
}

void View::OnEnabledChanged()
{
    SchedulePaint();
}

// Transformations -------------------------------------------------------------

gfx::Transform View::GetTransform() const
{
    return layer() ? layer()->transform() : gfx::Transform();
}

void View::SetTransform(const gfx::Transform& transform)
{
    if (transform.IsIdentity()) {
        if (layer()) {
            layer()->SetTransform(transform);
            if (!paint_to_layer_)
                DestroyLayer();
        } else {
            // Nothing.
        }
    } else {
        if (!layer())
            CreateLayer();
        layer()->SetTransform(transform);
        layer()->ScheduleDraw();
    }
}

void View::SetPaintToLayer(bool paint_to_layer)
{
    if (paint_to_layer_ == paint_to_layer)
        return;

    paint_to_layer_ = paint_to_layer;
    if (paint_to_layer_ && !layer()) {
        CreateLayer();
    } else if (!paint_to_layer_ && layer()) {
        DestroyLayer();
    }
}

scoped_ptr<ui::Layer> View::RecreateLayer()
{
    scoped_ptr<ui::Layer> old_layer = LayerOwner::RecreateLayer();
    Widget* widget = GetWidget();
    if (widget)
        widget->UpdateRootLayers();
    return old_layer;
}

// RTL positioning -------------------------------------------------------------

gfx::Rect View::GetMirroredBounds() const
{
    gfx::Rect bounds(bounds_);
    bounds.set_x(GetMirroredX());
    return bounds;
}

gfx::Point View::GetMirroredPosition() const
{
    return gfx::Point(GetMirroredX(), y());
}

int View::GetMirroredX() const
{
    return parent_ ? parent_->GetMirroredXForRect(bounds_) : x();
}

int View::GetMirroredXForRect(const gfx::Rect& bounds) const
{
    return base::i18n::IsRTL() ? (width() - bounds.x() - bounds.width()) : bounds.x();
}

int View::GetMirroredXInView(int x) const
{
    return base::i18n::IsRTL() ? width() - x : x;
}

int View::GetMirroredXWithWidthInView(int x, int w) const
{
    return base::i18n::IsRTL() ? width() - x - w : x;
}

// Layout ----------------------------------------------------------------------

void View::Layout()
{
    needs_layout_ = false;

    // If we have a layout manager, let it handle the layout for us.
    if (layout_manager_.get())
        layout_manager_->Layout(this);

    // Make sure to propagate the Layout() call to any children that haven't
    // received it yet through the layout manager and need to be laid out. This
    // is needed for the case when the child requires a layout but its bounds
    // weren't changed by the layout manager. If there is no layout manager, we
    // just propagate the Layout() call down the hierarchy, so whoever receives
    // the call can take appropriate action.
    for (int i = 0, count = child_count(); i < count; ++i) {
        View* child = child_at(i);
        if (child->needs_layout_ || !layout_manager_.get()) {
            TRACE_EVENT1("views", "View::Layout", "class", child->GetClassName());
            child->needs_layout_ = false;
            child->Layout();
        }
    }
}

void View::InvalidateLayout()
{
    // Always invalidate up. This is needed to handle the case of us already being
    // valid, but not our parent.
    needs_layout_ = true;
    if (parent_)
        parent_->InvalidateLayout();
}

LayoutManager* View::GetLayoutManager() const
{
    return layout_manager_.get();
}

void View::SetLayoutManager(LayoutManager* layout_manager)
{
    if (layout_manager_.get())
        layout_manager_->Uninstalled(this);

    layout_manager_.reset(layout_manager);
    if (layout_manager_.get())
        layout_manager_->Installed(this);
}

void View::SnapLayerToPixelBoundary()
{
    if (!layer())
        return;

    if (snap_layer_to_pixel_boundary_ && layer()->parent() && layer()->GetCompositor()) {
        ui::SnapLayerToPhysicalPixelBoundary(layer()->parent(), layer());
    } else {
        // Reset the offset.
        layer()->SetSubpixelPositionOffset(gfx::Vector2dF());
    }
}

// Attributes ------------------------------------------------------------------

const char* View::GetClassName() const
{
    return kViewClassName;
}

const View* View::GetAncestorWithClassName(const std::string& name) const
{
    for (const View* view = this; view; view = view->parent_) {
        if (!strcmp(view->GetClassName(), name.c_str()))
            return view;
    }
    return NULL;
}

View* View::GetAncestorWithClassName(const std::string& name)
{
    return const_cast<View*>(const_cast<const View*>(this)->GetAncestorWithClassName(name));
}

const View* View::GetViewByID(int id) const
{
    if (id == id_)
        return const_cast<View*>(this);

    for (int i = 0, count = child_count(); i < count; ++i) {
        const View* view = child_at(i)->GetViewByID(id);
        if (view)
            return view;
    }
    return NULL;
}

View* View::GetViewByID(int id)
{
    return const_cast<View*>(const_cast<const View*>(this)->GetViewByID(id));
}

void View::SetGroup(int gid)
{
    // Don't change the group id once it's set.
    DCHECK(group_ == -1 || group_ == gid);
    group_ = gid;
}

int View::GetGroup() const
{
    return group_;
}

bool View::IsGroupFocusTraversable() const
{
    return true;
}

void View::GetViewsInGroup(int group, Views* views)
{
    if (group_ == group)
        views->push_back(this);

    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->GetViewsInGroup(group, views);
}

View* View::GetSelectedViewForGroup(int group)
{
    Views views;
    GetWidget()->GetRootView()->GetViewsInGroup(group, &views);
    return views.empty() ? NULL : views[0];
}

// Coordinate conversion -------------------------------------------------------

// static
void View::ConvertPointToTarget(const View* source,
    const View* target,
    gfx::Point* point)
{
    DCHECK(source);
    DCHECK(target);
    if (source == target)
        return;

    const View* root = GetHierarchyRoot(target);
    CHECK_EQ(GetHierarchyRoot(source), root);

    if (source != root)
        source->ConvertPointForAncestor(root, point);

    if (target != root)
        target->ConvertPointFromAncestor(root, point);
}

// static
void View::ConvertRectToTarget(const View* source,
    const View* target,
    gfx::RectF* rect)
{
    DCHECK(source);
    DCHECK(target);
    if (source == target)
        return;

    const View* root = GetHierarchyRoot(target);
    CHECK_EQ(GetHierarchyRoot(source), root);

    if (source != root)
        source->ConvertRectForAncestor(root, rect);

    if (target != root)
        target->ConvertRectFromAncestor(root, rect);
}

// static
void View::ConvertPointToWidget(const View* src, gfx::Point* p)
{
    DCHECK(src);
    DCHECK(p);

    src->ConvertPointForAncestor(NULL, p);
}

// static
void View::ConvertPointFromWidget(const View* dest, gfx::Point* p)
{
    DCHECK(dest);
    DCHECK(p);

    dest->ConvertPointFromAncestor(NULL, p);
}

// static
void View::ConvertPointToScreen(const View* src, gfx::Point* p)
{
    DCHECK(src);
    DCHECK(p);

    // If the view is not connected to a tree, there's nothing we can do.
    const Widget* widget = src->GetWidget();
    if (widget) {
        ConvertPointToWidget(src, p);
        *p += widget->GetClientAreaBoundsInScreen().OffsetFromOrigin();
    }
}

// static
void View::ConvertPointFromScreen(const View* dst, gfx::Point* p)
{
    DCHECK(dst);
    DCHECK(p);

    const views::Widget* widget = dst->GetWidget();
    if (!widget)
        return;
    *p -= widget->GetClientAreaBoundsInScreen().OffsetFromOrigin();
    views::View::ConvertPointFromWidget(dst, p);
}

gfx::Rect View::ConvertRectToParent(const gfx::Rect& rect) const
{
    gfx::RectF x_rect = gfx::RectF(rect);
    GetTransform().TransformRect(&x_rect);
    x_rect.Offset(GetMirroredPosition().OffsetFromOrigin());
    // Pixels we partially occupy in the parent should be included.
    return gfx::ToEnclosingRect(x_rect);
}

gfx::Rect View::ConvertRectToWidget(const gfx::Rect& rect) const
{
    gfx::Rect x_rect = rect;
    for (const View* v = this; v; v = v->parent_)
        x_rect = v->ConvertRectToParent(x_rect);
    return x_rect;
}

// Painting --------------------------------------------------------------------

void View::SchedulePaint()
{
    SchedulePaintInRect(GetLocalBounds());
}

void View::SchedulePaintInRect(const gfx::Rect& rect)
{
    if (!visible_)
        return;

    if (layer()) {
        layer()->SchedulePaint(rect);
    } else if (parent_) {
        // Translate the requested paint rect to the parent's coordinate system
        // then pass this notification up to the parent.
        parent_->SchedulePaintInRect(ConvertRectToParent(rect));
    }
}

void View::Paint(const ui::PaintContext& parent_context)
{
    if (!visible_)
        return;
    if (size().IsEmpty())
        return;

    gfx::Vector2d offset_to_parent;
    if (!layer()) {
        // If the View has a layer() then it is a paint root. Otherwise, we need to
        // add the offset from the parent into the total offset from the paint root.
        DCHECK(parent() || bounds().origin() == gfx::Point());
        offset_to_parent = GetMirroredPosition().OffsetFromOrigin();
    }
    ui::PaintContext context(parent_context, offset_to_parent);

    bool is_invalidated = true;
    if (context.CanCheckInvalid()) {
#if DCHECK_IS_ON()
        gfx::Vector2d offset;
        context.Visited(this);
        View* view = this;
        while (view->parent() && !view->layer()) {
            DCHECK(view->GetTransform().IsIdentity());
            offset += view->GetMirroredPosition().OffsetFromOrigin();
            view = view->parent();
        }
        // The offset in the PaintContext should be the offset up to the paint root,
        // which we compute and verify here.
        DCHECK_EQ(context.PaintOffset().x(), offset.x());
        DCHECK_EQ(context.PaintOffset().y(), offset.y());
        // The above loop will stop when |view| is the paint root, which should be
        // the root of the current paint walk, as verified by storing the root in
        // the PaintContext.
        DCHECK_EQ(context.RootVisited(), view);
#endif

        // If the View wasn't invalidated, don't waste time painting it, the output
        // would be culled.
        is_invalidated = context.IsRectInvalid(GetLocalBounds());
    }

    TRACE_EVENT1("views", "View::Paint", "class", GetClassName());

    // If the view is backed by a layer, it should paint with itself as the origin
    // rather than relative to its parent.
    bool paint_relative_to_parent = !layer();

    // TODO(danakj): Rework clip and transform recorder usage here to use
    // std::optional once we can do so.
    ui::ClipRecorder clip_recorder(parent_context);
    if (paint_relative_to_parent) {
        // Set the clip rect to the bounds of this View. Note that the X (or left)
        // position we pass to ClipRect takes into consideration whether or not the
        // View uses a right-to-left layout so that we paint the View in its
        // mirrored position if need be.
        gfx::Rect clip_rect_in_parent = bounds();
        clip_rect_in_parent.Inset(clip_insets_);
        if (parent_)
            clip_rect_in_parent.set_x(
                parent_->GetMirroredXForRect(clip_rect_in_parent));
        clip_recorder.ClipRect(clip_rect_in_parent);
    }

    ui::TransformRecorder transform_recorder(context);
    if (paint_relative_to_parent) {
        // Translate the graphics such that 0,0 corresponds to where
        // this View is located relative to its parent.
        gfx::Transform transform_from_parent;
        gfx::Vector2d offset_from_parent = GetMirroredPosition().OffsetFromOrigin();
        transform_from_parent.Translate(offset_from_parent.x(),
            offset_from_parent.y());
        transform_from_parent.PreconcatTransform(GetTransform());
        transform_recorder.Transform(transform_from_parent, size());
    }

    // Note that the cache is not aware of the offset of the view
    // relative to the parent since painting is always done relative to
    // the top left of the individual view.
    if (is_invalidated || !paint_cache_.UseCache(context, size())) {
        ui::PaintRecorder recorder(context, size(), &paint_cache_);
        gfx::Canvas* canvas = recorder.canvas();

        // If the View we are about to paint requested the canvas to be flipped, we
        // should change the transform appropriately.
        // The canvas mirroring is undone once the View is done painting so that we
        // don't pass the canvas with the mirrored transform to Views that didn't
        // request the canvas to be flipped.
        if (FlipCanvasOnPaintForRTLUI()) {
            canvas->Translate(gfx::Vector2d(width(), 0));
            canvas->Scale(-1, 1);
        }

        // Delegate painting the contents of the View to the virtual OnPaint method.
        OnPaint(canvas);
    }

    // View::Paint() recursion over the subtree.
    PaintChildren(context);
}

void View::set_background(Background* b)
{
    background_.reset(b);
}

void View::SetBorder(scoped_ptr<Border> b)
{
    border_ = std::move(b);
}

const ui::ThemeProvider* View::GetThemeProvider() const
{
    const Widget* widget = GetWidget();
    return widget ? widget->GetThemeProvider() : nullptr;
}

const ui::NativeTheme* View::GetNativeTheme() const
{
    const Widget* widget = GetWidget();
    if (widget)
        return widget->GetNativeTheme();

#if defined(OS_WIN)
    // On Windows, ui::NativeTheme::GetInstanceForWeb() returns NativeThemeWinAura
    // because that's what the renderer wants, but Views should default to
    // NativeThemeWin. TODO(estade): clean this up, see http://crbug.com/558029
    return ui::NativeThemeWin::instance();
#else
    return ui::NativeTheme::GetInstanceForWeb();
#endif
}

// RTL painting ----------------------------------------------------------------

void View::EnableCanvasFlippingForRTLUI(bool enable)
{
    flip_canvas_on_paint_for_rtl_ui_ = enable;
}

// Input -----------------------------------------------------------------------

View* View::GetEventHandlerForPoint(const gfx::Point& point)
{
    return GetEventHandlerForRect(gfx::Rect(point, gfx::Size(1, 1)));
}

View* View::GetEventHandlerForRect(const gfx::Rect& rect)
{
    return GetEffectiveViewTargeter()->TargetForRect(this, rect);
}

bool View::CanProcessEventsWithinSubtree() const
{
    return true;
}

View* View::GetTooltipHandlerForPoint(const gfx::Point& point)
{
    // TODO(tdanderson): Move this implementation into ViewTargetDelegate.
    if (!HitTestPoint(point) || !CanProcessEventsWithinSubtree())
        return NULL;

    // Walk the child Views recursively looking for the View that most
    // tightly encloses the specified point.
    for (int i = child_count() - 1; i >= 0; --i) {
        View* child = child_at(i);
        if (!child->visible())
            continue;

        gfx::Point point_in_child_coords(point);
        ConvertPointToTarget(this, child, &point_in_child_coords);
        View* handler = child->GetTooltipHandlerForPoint(point_in_child_coords);
        if (handler)
            return handler;
    }
    return this;
}

gfx::NativeCursor View::GetCursor(const ui::MouseEvent& event)
{
#if defined(OS_WIN)
    static ui::Cursor arrow;
    if (!arrow.platform())
        arrow.SetPlatformCursor(LoadCursor(NULL, IDC_ARROW));
    return arrow;
#else
    return gfx::kNullCursor;
#endif
}

bool View::HitTestPoint(const gfx::Point& point) const
{
    return HitTestRect(gfx::Rect(point, gfx::Size(1, 1)));
}

bool View::HitTestRect(const gfx::Rect& rect) const
{
    return GetEffectiveViewTargeter()->DoesIntersectRect(this, rect);
}

bool View::IsMouseHovered() const
{
    // If we haven't yet been placed in an onscreen view hierarchy, we can't be
    // hovered.
    if (!GetWidget())
        return false;

    // If mouse events are disabled, then the mouse cursor is invisible and
    // is therefore not hovering over this button.
    if (!GetWidget()->IsMouseEventsEnabled())
        return false;

    gfx::Point cursor_pos(gfx::Screen::GetScreen()->GetCursorScreenPoint());
    ConvertPointFromScreen(this, &cursor_pos);
    return HitTestPoint(cursor_pos);
}

bool View::OnMousePressed(const ui::MouseEvent& event)
{
    return false;
}

bool View::OnMouseDragged(const ui::MouseEvent& event)
{
    return false;
}

void View::OnMouseReleased(const ui::MouseEvent& event)
{
}

void View::OnMouseCaptureLost()
{
}

void View::OnMouseMoved(const ui::MouseEvent& event)
{
}

void View::OnMouseEntered(const ui::MouseEvent& event)
{
}

void View::OnMouseExited(const ui::MouseEvent& event)
{
}

void View::SetMouseHandler(View* new_mouse_handler)
{
    // |new_mouse_handler| may be NULL.
    if (parent_)
        parent_->SetMouseHandler(new_mouse_handler);
}

bool View::OnKeyPressed(const ui::KeyEvent& event)
{
    return false;
}

bool View::OnKeyReleased(const ui::KeyEvent& event)
{
    return false;
}

bool View::OnMouseWheel(const ui::MouseWheelEvent& event)
{
    return false;
}

void View::OnKeyEvent(ui::KeyEvent* event)
{
    bool consumed = (event->type() == ui::ET_KEY_PRESSED) ? OnKeyPressed(*event) : OnKeyReleased(*event);
    if (consumed)
        event->StopPropagation();
}

void View::OnMouseEvent(ui::MouseEvent* event)
{
    switch (event->type()) {
    case ui::ET_MOUSE_PRESSED:
        if (ProcessMousePressed(*event))
            event->SetHandled();
        return;

    case ui::ET_MOUSE_MOVED:
        if ((event->flags() & (ui::EF_LEFT_MOUSE_BUTTON | ui::EF_RIGHT_MOUSE_BUTTON | ui::EF_MIDDLE_MOUSE_BUTTON)) == 0) {
            OnMouseMoved(*event);
            return;
        }
        // FALL-THROUGH
    case ui::ET_MOUSE_DRAGGED:
        if (ProcessMouseDragged(*event))
            event->SetHandled();
        return;

    case ui::ET_MOUSE_RELEASED:
        ProcessMouseReleased(*event);
        return;

    case ui::ET_MOUSEWHEEL:
        if (OnMouseWheel(*static_cast<ui::MouseWheelEvent*>(event)))
            event->SetHandled();
        break;

    case ui::ET_MOUSE_ENTERED:
        if (event->flags() & ui::EF_TOUCH_ACCESSIBILITY)
            NotifyAccessibilityEvent(ui::AX_EVENT_HOVER, true);
        OnMouseEntered(*event);
        break;

    case ui::ET_MOUSE_EXITED:
        OnMouseExited(*event);
        break;

    default:
        return;
    }
}

void View::OnScrollEvent(ui::ScrollEvent* event)
{
}

void View::OnTouchEvent(ui::TouchEvent* event)
{
    NOTREACHED() << "Views should not receive touch events.";
}

void View::OnGestureEvent(ui::GestureEvent* event)
{
}

const ui::InputMethod* View::GetInputMethod() const
{
    Widget* widget = const_cast<Widget*>(GetWidget());
    return widget ? const_cast<const ui::InputMethod*>(widget->GetInputMethod())
                  : nullptr;
}

scoped_ptr<ViewTargeter>
View::SetEventTargeter(scoped_ptr<ViewTargeter> targeter)
{
    scoped_ptr<ViewTargeter> old_targeter = std::move(targeter_);
    targeter_ = std::move(targeter);
    return old_targeter;
}

ViewTargeter* View::GetEffectiveViewTargeter() const
{
    DCHECK(GetWidget());
    ViewTargeter* view_targeter = targeter();
    if (!view_targeter)
        view_targeter = GetWidget()->GetRootView()->targeter();
    CHECK(view_targeter);
    return view_targeter;
}

bool View::CanAcceptEvent(const ui::Event& event)
{
    return IsDrawn();
}

ui::EventTarget* View::GetParentTarget()
{
    return parent_;
}

scoped_ptr<ui::EventTargetIterator> View::GetChildIterator() const
{
    return make_scoped_ptr(new ui::EventTargetIteratorImpl<View>(children_));
}

ui::EventTargeter* View::GetEventTargeter()
{
    return targeter_.get();
}

void View::ConvertEventToTarget(ui::EventTarget* target,
    ui::LocatedEvent* event)
{
    event->ConvertLocationToTarget(this, static_cast<View*>(target));
}

// Accelerators ----------------------------------------------------------------

void View::AddAccelerator(const ui::Accelerator& accelerator)
{
    if (!accelerators_.get())
        accelerators_.reset(new std::vector<ui::Accelerator>());

    if (!ContainsValue(*accelerators_.get(), accelerator))
        accelerators_->push_back(accelerator);

    RegisterPendingAccelerators();
}

void View::RemoveAccelerator(const ui::Accelerator& accelerator)
{
    if (!accelerators_.get()) {
        NOTREACHED() << "Removing non-existing accelerator";
        return;
    }

    std::vector<ui::Accelerator>::iterator i(
        std::find(accelerators_->begin(), accelerators_->end(), accelerator));
    if (i == accelerators_->end()) {
        NOTREACHED() << "Removing non-existing accelerator";
        return;
    }

    size_t index = i - accelerators_->begin();
    accelerators_->erase(i);
    if (index >= registered_accelerator_count_) {
        // The accelerator is not registered to FocusManager.
        return;
    }
    --registered_accelerator_count_;

    // Providing we are attached to a Widget and registered with a focus manager,
    // we should de-register from that focus manager now.
    if (GetWidget() && accelerator_focus_manager_)
        accelerator_focus_manager_->UnregisterAccelerator(accelerator, this);
}

void View::ResetAccelerators()
{
    if (accelerators_.get())
        UnregisterAccelerators(false);
}

bool View::AcceleratorPressed(const ui::Accelerator& accelerator)
{
    return false;
}

bool View::CanHandleAccelerators() const
{
    const Widget* widget = GetWidget();
    if (!enabled() || !IsDrawn() || !widget || !widget->IsVisible())
        return false;
#if defined(USE_AURA) && !defined(OS_CHROMEOS)
    // Non-ChromeOS aura windows have an associated FocusManagerEventHandler which
    // adds currently focused view as an event PreTarget (see
    // DesktopNativeWidgetAura::InitNativeWidget). However, the focused view isn't
    // always the right view to handle accelerators: It should only handle them
    // when active. Only top level widgets can be active, so for child widgets
    // check if they are focused instead. ChromeOS also behaves different than
    // Linux when an extension popup is about to handle the accelerator.
    bool child = widget && widget->GetTopLevelWidget() != widget;
    bool focus_in_child = widget && widget->GetRootView()->Contains(GetFocusManager()->GetFocusedView());
    if ((child && !focus_in_child) || (!child && !widget->IsActive()))
        return false;
#endif
    return true;
}

// Focus -----------------------------------------------------------------------

bool View::HasFocus() const
{
    const FocusManager* focus_manager = GetFocusManager();
    return focus_manager && (focus_manager->GetFocusedView() == this);
}

View* View::GetNextFocusableView()
{
    return next_focusable_view_;
}

const View* View::GetNextFocusableView() const
{
    return next_focusable_view_;
}

View* View::GetPreviousFocusableView()
{
    return previous_focusable_view_;
}

void View::SetNextFocusableView(View* view)
{
    if (view)
        view->previous_focusable_view_ = this;
    next_focusable_view_ = view;
}

void View::SetFocusable(bool focusable)
{
    if (focusable_ == focusable)
        return;

    focusable_ = focusable;
    AdvanceFocusIfNecessary();
}

bool View::IsFocusable() const
{
    return focusable_ && enabled_ && IsDrawn();
}

bool View::IsAccessibilityFocusable() const
{
    return (focusable_ || accessibility_focusable_) && enabled_ && IsDrawn();
}

void View::SetAccessibilityFocusable(bool accessibility_focusable)
{
    if (accessibility_focusable_ == accessibility_focusable)
        return;

    accessibility_focusable_ = accessibility_focusable;
    AdvanceFocusIfNecessary();
}

FocusManager* View::GetFocusManager()
{
    Widget* widget = GetWidget();
    return widget ? widget->GetFocusManager() : NULL;
}

const FocusManager* View::GetFocusManager() const
{
    const Widget* widget = GetWidget();
    return widget ? widget->GetFocusManager() : NULL;
}

void View::RequestFocus()
{
    FocusManager* focus_manager = GetFocusManager();
    if (focus_manager && IsFocusable())
        focus_manager->SetFocusedView(this);
}

bool View::SkipDefaultKeyEventProcessing(const ui::KeyEvent& event)
{
    return false;
}

FocusTraversable* View::GetFocusTraversable()
{
    return NULL;
}

FocusTraversable* View::GetPaneFocusTraversable()
{
    return NULL;
}

// Tooltips --------------------------------------------------------------------

bool View::GetTooltipText(const gfx::Point& p, base::string16* tooltip) const
{
    return false;
}

bool View::GetTooltipTextOrigin(const gfx::Point& p, gfx::Point* loc) const
{
    return false;
}

// Context menus ---------------------------------------------------------------

void View::ShowContextMenu(const gfx::Point& p,
    ui::MenuSourceType source_type)
{
    if (!context_menu_controller_)
        return;

    context_menu_controller_->ShowContextMenuForView(this, p, source_type);
}

// static
bool View::ShouldShowContextMenuOnMousePress()
{
    return kContextMenuOnMousePress;
}

gfx::Point View::GetKeyboardContextMenuLocation()
{
    gfx::Rect vis_bounds = GetVisibleBounds();
    gfx::Point screen_point(vis_bounds.x() + vis_bounds.width() / 2,
        vis_bounds.y() + vis_bounds.height() / 2);
    ConvertPointToScreen(this, &screen_point);
    return screen_point;
}

// Drag and drop ---------------------------------------------------------------

bool View::GetDropFormats(int* formats,
    std::set<ui::Clipboard::FormatType>* format_types)
{
    return false;
}

bool View::AreDropTypesRequired()
{
    return false;
}

bool View::CanDrop(const OSExchangeData& data)
{
    // TODO(sky): when I finish up migration, this should default to true.
    return false;
}

void View::OnDragEntered(const ui::DropTargetEvent& event)
{
}

int View::OnDragUpdated(const ui::DropTargetEvent& event)
{
    return ui::DragDropTypes::DRAG_NONE;
}

void View::OnDragExited()
{
}

int View::OnPerformDrop(const ui::DropTargetEvent& event)
{
    return ui::DragDropTypes::DRAG_NONE;
}

void View::OnDragDone()
{
}

// static
bool View::ExceededDragThreshold(const gfx::Vector2d& delta)
{
    return (abs(delta.x()) > GetHorizontalDragThreshold() || abs(delta.y()) > GetVerticalDragThreshold());
}

// Accessibility----------------------------------------------------------------

gfx::NativeViewAccessible View::GetNativeViewAccessible()
{
    if (!native_view_accessibility_)
        native_view_accessibility_ = NativeViewAccessibility::Create(this);
    if (native_view_accessibility_)
        return native_view_accessibility_->GetNativeObject();
    return NULL;
}

void View::NotifyAccessibilityEvent(
    ui::AXEvent event_type,
    bool send_native_event)
{
    if (ViewsDelegate::GetInstance())
        ViewsDelegate::GetInstance()->NotifyAccessibilityEvent(this, event_type);

    if (send_native_event && GetWidget()) {
        if (!native_view_accessibility_)
            native_view_accessibility_ = NativeViewAccessibility::Create(this);
        if (native_view_accessibility_)
            native_view_accessibility_->NotifyAccessibilityEvent(event_type);
    }
}

// Scrolling -------------------------------------------------------------------

void View::ScrollRectToVisible(const gfx::Rect& rect)
{
    // We must take RTL UI mirroring into account when adjusting the position of
    // the region.
    if (parent_) {
        gfx::Rect scroll_rect(rect);
        scroll_rect.Offset(GetMirroredX(), y());
        parent_->ScrollRectToVisible(scroll_rect);
    }
}

int View::GetPageScrollIncrement(ScrollView* scroll_view,
    bool is_horizontal, bool is_positive)
{
    return 0;
}

int View::GetLineScrollIncrement(ScrollView* scroll_view,
    bool is_horizontal, bool is_positive)
{
    return 0;
}

////////////////////////////////////////////////////////////////////////////////
// View, protected:

// Size and disposition --------------------------------------------------------

void View::OnBoundsChanged(const gfx::Rect& previous_bounds)
{
}

void View::PreferredSizeChanged()
{
    InvalidateLayout();
    if (parent_)
        parent_->ChildPreferredSizeChanged(this);
}

bool View::GetNeedsNotificationWhenVisibleBoundsChange() const
{
    return false;
}

void View::OnVisibleBoundsChanged()
{
}

// Tree operations -------------------------------------------------------------

void View::ViewHierarchyChanged(const ViewHierarchyChangedDetails& details)
{
}

void View::VisibilityChanged(View* starting_from, bool is_visible)
{
}

void View::NativeViewHierarchyChanged()
{
    FocusManager* focus_manager = GetFocusManager();
    if (accelerator_focus_manager_ != focus_manager) {
        UnregisterAccelerators(true);

        if (focus_manager)
            RegisterPendingAccelerators();
    }
}

// Painting --------------------------------------------------------------------

void View::PaintChildren(const ui::PaintContext& context)
{
    TRACE_EVENT1("views", "View::PaintChildren", "class", GetClassName());
    for (int i = 0, count = child_count(); i < count; ++i)
        if (!child_at(i)->layer())
            child_at(i)->Paint(context);
}

void View::OnPaint(gfx::Canvas* canvas)
{
    TRACE_EVENT1("views", "View::OnPaint", "class", GetClassName());
    OnPaintBackground(canvas);
    OnPaintBorder(canvas);
}

void View::OnPaintBackground(gfx::Canvas* canvas)
{
    if (background_.get()) {
        TRACE_EVENT2("views", "View::OnPaintBackground",
            "width", canvas->sk_canvas()->getBaseLayerSize().width(),
            "height", canvas->sk_canvas()->getBaseLayerSize().height());
        background_->Paint(canvas, this);
    }
}

void View::OnPaintBorder(gfx::Canvas* canvas)
{
    if (border_.get()) {
        TRACE_EVENT2("views", "View::OnPaintBorder",
            "width", canvas->sk_canvas()->getBaseLayerSize().width(),
            "height", canvas->sk_canvas()->getBaseLayerSize().height());
        border_->Paint(*this, canvas);
    }
}

// Accelerated Painting --------------------------------------------------------

void View::SetFillsBoundsOpaquely(bool fills_bounds_opaquely)
{
    // This method should not have the side-effect of creating the layer.
    if (layer())
        layer()->SetFillsBoundsOpaquely(fills_bounds_opaquely);
}

gfx::Vector2d View::CalculateOffsetToAncestorWithLayer(
    ui::Layer** layer_parent)
{
    if (layer()) {
        if (layer_parent)
            *layer_parent = layer();
        return gfx::Vector2d();
    }
    if (!parent_)
        return gfx::Vector2d();

    return gfx::Vector2d(GetMirroredX(), y()) + parent_->CalculateOffsetToAncestorWithLayer(layer_parent);
}

void View::UpdateParentLayer()
{
    if (!layer())
        return;

    ui::Layer* parent_layer = NULL;
    gfx::Vector2d offset(GetMirroredX(), y());

    if (parent_)
        offset += parent_->CalculateOffsetToAncestorWithLayer(&parent_layer);

    ReparentLayer(offset, parent_layer);
}

void View::MoveLayerToParent(ui::Layer* parent_layer,
    const gfx::Point& point)
{
    gfx::Point local_point(point);
    if (parent_layer != layer())
        local_point.Offset(GetMirroredX(), y());
    if (layer() && parent_layer != layer()) {
        parent_layer->Add(layer());
        SetLayerBounds(gfx::Rect(local_point.x(), local_point.y(),
            width(), height()));
    } else {
        for (int i = 0, count = child_count(); i < count; ++i)
            child_at(i)->MoveLayerToParent(parent_layer, local_point);
    }
}

void View::UpdateLayerVisibility()
{
    bool visible = visible_;
    for (const View* v = parent_; visible && v && !v->layer(); v = v->parent_)
        visible = v->visible();

    UpdateChildLayerVisibility(visible);
}

void View::UpdateChildLayerVisibility(bool ancestor_visible)
{
    if (layer()) {
        layer()->SetVisible(ancestor_visible && visible_);
    } else {
        for (int i = 0, count = child_count(); i < count; ++i)
            child_at(i)->UpdateChildLayerVisibility(ancestor_visible && visible_);
    }
}

void View::UpdateChildLayerBounds(const gfx::Vector2d& offset)
{
    if (layer()) {
        SetLayerBounds(GetLocalBounds() + offset);
    } else {
        for (int i = 0, count = child_count(); i < count; ++i) {
            View* child = child_at(i);
            child->UpdateChildLayerBounds(
                offset + gfx::Vector2d(child->GetMirroredX(), child->y()));
        }
    }
}

void View::OnPaintLayer(const ui::PaintContext& context)
{
    Paint(context);
}

void View::OnDelegatedFrameDamage(
    const gfx::Rect& damage_rect_in_dip)
{
}

void View::OnDeviceScaleFactorChanged(float device_scale_factor)
{
    snap_layer_to_pixel_boundary_ = (device_scale_factor - std::floor(device_scale_factor)) != 0.0f;
    SnapLayerToPixelBoundary();
    // Repainting with new scale factor will paint the content at the right scale.
}

base::Closure View::PrepareForLayerBoundsChange()
{
    return base::Closure();
}

void View::ReorderLayers()
{
    View* v = this;
    while (v && !v->layer())
        v = v->parent();

    Widget* widget = GetWidget();
    if (!v) {
        if (widget) {
            ui::Layer* layer = widget->GetLayer();
            if (layer)
                widget->GetRootView()->ReorderChildLayers(layer);
        }
    } else {
        v->ReorderChildLayers(v->layer());
    }

    if (widget) {
        // Reorder the widget's child NativeViews in case a child NativeView is
        // associated with a view (eg via a NativeViewHost). Always do the
        // reordering because the associated NativeView's layer (if it has one)
        // is parented to the widget's layer regardless of whether the host view has
        // an ancestor with a layer.
        widget->ReorderNativeViews();
    }
}

void View::ReorderChildLayers(ui::Layer* parent_layer)
{
    if (layer() && layer() != parent_layer) {
        DCHECK_EQ(parent_layer, layer()->parent());
        parent_layer->StackAtBottom(layer());
    } else {
        // Iterate backwards through the children so that a child with a layer
        // which is further to the back is stacked above one which is further to
        // the front.
        for (Views::reverse_iterator it(children_.rbegin());
             it != children_.rend(); ++it) {
            (*it)->ReorderChildLayers(parent_layer);
        }
    }
}

// Input -----------------------------------------------------------------------

View::DragInfo* View::GetDragInfo()
{
    return parent_ ? parent_->GetDragInfo() : NULL;
}

// Focus -----------------------------------------------------------------------

void View::OnFocus()
{
    // TODO(beng): Investigate whether it's possible for us to move this to
    //             Focus().
    // By default, we clear the native focus. This ensures that no visible native
    // view as the focus and that we still receive keyboard inputs.
    FocusManager* focus_manager = GetFocusManager();
    if (focus_manager)
        focus_manager->ClearNativeFocus();

    // TODO(beng): Investigate whether it's possible for us to move this to
    //             Focus().
    // Notify assistive technologies of the focus change.
    NotifyAccessibilityEvent(ui::AX_EVENT_FOCUS, true);
}

void View::OnBlur()
{
}

void View::Focus()
{
    OnFocus();
}

void View::Blur()
{
    OnBlur();
}

// Tooltips --------------------------------------------------------------------

void View::TooltipTextChanged()
{
    Widget* widget = GetWidget();
    // TooltipManager may be null if there is a problem creating it.
    if (widget && widget->GetTooltipManager())
        widget->GetTooltipManager()->TooltipTextChanged(this);
}

// Drag and drop ---------------------------------------------------------------

int View::GetDragOperations(const gfx::Point& press_pt)
{
    return drag_controller_ ? drag_controller_->GetDragOperationsForView(this, press_pt) : ui::DragDropTypes::DRAG_NONE;
}

void View::WriteDragData(const gfx::Point& press_pt, OSExchangeData* data)
{
    DCHECK(drag_controller_);
    drag_controller_->WriteDragDataForView(this, press_pt, data);
}

bool View::InDrag() const
{
    const Widget* widget = GetWidget();
    return widget ? widget->dragged_view() == this : false;
}

int View::GetHorizontalDragThreshold()
{
    // TODO(jennyz): This value may need to be adjusted for different platforms
    // and for different display density.
    return kDefaultHorizontalDragThreshold;
}

int View::GetVerticalDragThreshold()
{
    // TODO(jennyz): This value may need to be adjusted for different platforms
    // and for different display density.
    return kDefaultVerticalDragThreshold;
}

// Debugging -------------------------------------------------------------------

#if !defined(NDEBUG)

std::string View::PrintViewGraph(bool first)
{
    return DoPrintViewGraph(first, this);
}

std::string View::DoPrintViewGraph(bool first, View* view_with_children)
{
    // 64-bit pointer = 16 bytes of hex + "0x" + '\0' = 19.
    const size_t kMaxPointerStringLength = 19;

    std::string result;

    if (first)
        result.append("digraph {\n");

    // Node characteristics.
    char p[kMaxPointerStringLength];

    const std::string class_name(GetClassName());
    size_t base_name_index = class_name.find_last_of('/');
    if (base_name_index == std::string::npos)
        base_name_index = 0;
    else
        base_name_index++;

    char bounds_buffer[512];

    // Information about current node.
    base::snprintf(p, arraysize(bounds_buffer), "%p", view_with_children);
    result.append("  N");
    result.append(p + 2);
    result.append(" [label=\"");

    result.append(class_name.substr(base_name_index).c_str());

    base::snprintf(bounds_buffer,
        arraysize(bounds_buffer),
        "\\n bounds: (%d, %d), (%dx%d)",
        bounds().x(),
        bounds().y(),
        bounds().width(),
        bounds().height());
    result.append(bounds_buffer);

    gfx::DecomposedTransform decomp;
    if (!GetTransform().IsIdentity() && gfx::DecomposeTransform(&decomp, GetTransform())) {
        base::snprintf(bounds_buffer,
            arraysize(bounds_buffer),
            "\\n translation: (%f, %f)",
            decomp.translate[0],
            decomp.translate[1]);
        result.append(bounds_buffer);

        base::snprintf(bounds_buffer,
            arraysize(bounds_buffer),
            "\\n rotation: %3.2f",
            std::acos(decomp.quaternion[3]) * 360.0 / M_PI);
        result.append(bounds_buffer);

        base::snprintf(bounds_buffer,
            arraysize(bounds_buffer),
            "\\n scale: (%2.4f, %2.4f)",
            decomp.scale[0],
            decomp.scale[1]);
        result.append(bounds_buffer);
    }

    result.append("\"");
    if (!parent_)
        result.append(", shape=box");
    if (layer()) {
        if (layer()->has_external_content())
            result.append(", color=green");
        else
            result.append(", color=red");

        if (layer()->fills_bounds_opaquely())
            result.append(", style=filled");
    }
    result.append("]\n");

    // Link to parent.
    if (parent_) {
        char pp[kMaxPointerStringLength];

        base::snprintf(pp, kMaxPointerStringLength, "%p", parent_);
        result.append("  N");
        result.append(pp + 2);
        result.append(" -> N");
        result.append(p + 2);
        result.append("\n");
    }

    // Children.
    for (int i = 0, count = view_with_children->child_count(); i < count; ++i)
        result.append(view_with_children->child_at(i)->PrintViewGraph(false));

    if (first)
        result.append("}\n");

    return result;
}
#endif

////////////////////////////////////////////////////////////////////////////////
// View, private:

// DropInfo --------------------------------------------------------------------

void View::DragInfo::Reset()
{
    possible_drag = false;
    start_pt = gfx::Point();
}

void View::DragInfo::PossibleDrag(const gfx::Point& p)
{
    possible_drag = true;
    start_pt = p;
}

// Painting --------------------------------------------------------------------

void View::SchedulePaintBoundsChanged(SchedulePaintType type)
{
    // If we have a layer and the View's size did not change, we do not need to
    // schedule any paints since the layer will be redrawn at its new location
    // during the next Draw() cycle in the compositor.
    if (!layer() || type == SCHEDULE_PAINT_SIZE_CHANGED) {
        // Otherwise, if the size changes or we don't have a layer then we need to
        // use SchedulePaint to invalidate the area occupied by the View.
        SchedulePaint();
    } else if (parent_ && type == SCHEDULE_PAINT_SIZE_SAME) {
        // The compositor doesn't Draw() until something on screen changes, so
        // if our position changes but nothing is being animated on screen, then
        // tell the compositor to redraw the scene. We know layer() exists due to
        // the above if clause.
        layer()->ScheduleDraw();
    }
}

void View::SchedulePaintOnParent()
{
    if (parent_) {
        // Translate the requested paint rect to the parent's coordinate system
        // then pass this notification up to the parent.
        parent_->SchedulePaintInRect(ConvertRectToParent(GetLocalBounds()));
    }
}

// Tree operations -------------------------------------------------------------

void View::DoRemoveChildView(View* view,
    bool update_focus_cycle,
    bool update_tool_tip,
    bool delete_removed_view,
    View* new_parent)
{
    DCHECK(view);

    const Views::iterator i(std::find(children_.begin(), children_.end(), view));
    scoped_ptr<View> view_to_be_deleted;
    if (i != children_.end()) {
        if (update_focus_cycle) {
            // Let's remove the view from the focus traversal.
            View* next_focusable = view->next_focusable_view_;
            View* prev_focusable = view->previous_focusable_view_;
            if (prev_focusable)
                prev_focusable->next_focusable_view_ = next_focusable;
            if (next_focusable)
                next_focusable->previous_focusable_view_ = prev_focusable;
        }

        Widget* widget = GetWidget();
        if (widget) {
            UnregisterChildrenForVisibleBoundsNotification(view);
            if (view->visible())
                view->SchedulePaint();

            if (!new_parent || new_parent->GetWidget() != widget)
                widget->NotifyWillRemoveView(view);
        }

        view->PropagateRemoveNotifications(this, new_parent);
        view->parent_ = NULL;
        view->UpdateLayerVisibility();

        if (delete_removed_view && !view->owned_by_client_)
            view_to_be_deleted.reset(view);

        children_.erase(i);
    }

    if (update_tool_tip)
        UpdateTooltip();

    if (layout_manager_.get())
        layout_manager_->ViewRemoved(this, view);
}

void View::PropagateRemoveNotifications(View* old_parent, View* new_parent)
{
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->PropagateRemoveNotifications(old_parent, new_parent);

    ViewHierarchyChangedDetails details(false, old_parent, this, new_parent);
    for (View* v = this; v; v = v->parent_)
        v->ViewHierarchyChangedImpl(true, details);
}

void View::PropagateAddNotifications(
    const ViewHierarchyChangedDetails& details)
{
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->PropagateAddNotifications(details);
    ViewHierarchyChangedImpl(true, details);
}

void View::PropagateNativeViewHierarchyChanged()
{
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->PropagateNativeViewHierarchyChanged();
    NativeViewHierarchyChanged();
}

void View::ViewHierarchyChangedImpl(
    bool register_accelerators,
    const ViewHierarchyChangedDetails& details)
{
    if (register_accelerators) {
        if (details.is_add) {
            // If you get this registration, you are part of a subtree that has been
            // added to the view hierarchy.
            if (GetFocusManager())
                RegisterPendingAccelerators();
        } else {
            if (details.child == this)
                UnregisterAccelerators(true);
        }
    }

    if (details.is_add && layer() && !layer()->parent()) {
        UpdateParentLayer();
        Widget* widget = GetWidget();
        if (widget)
            widget->UpdateRootLayers();
    } else if (!details.is_add && details.child == this) {
        // Make sure the layers belonging to the subtree rooted at |child| get
        // removed from layers that do not belong in the same subtree.
        OrphanLayers();
        Widget* widget = GetWidget();
        if (widget)
            widget->UpdateRootLayers();
    }

    ViewHierarchyChanged(details);
    details.parent->needs_layout_ = true;
}

void View::PropagateNativeThemeChanged(const ui::NativeTheme* theme)
{
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->PropagateNativeThemeChanged(theme);
    OnNativeThemeChanged(theme);
}

// Size and disposition --------------------------------------------------------

void View::PropagateVisibilityNotifications(View* start, bool is_visible)
{
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->PropagateVisibilityNotifications(start, is_visible);
    VisibilityChangedImpl(start, is_visible);
}

void View::VisibilityChangedImpl(View* starting_from, bool is_visible)
{
    VisibilityChanged(starting_from, is_visible);
}

void View::BoundsChanged(const gfx::Rect& previous_bounds)
{
    if (visible_) {
        // Paint the new bounds.
        SchedulePaintBoundsChanged(
            bounds_.size() == previous_bounds.size() ? SCHEDULE_PAINT_SIZE_SAME : SCHEDULE_PAINT_SIZE_CHANGED);
    }

    if (layer()) {
        if (parent_) {
            SetLayerBounds(GetLocalBounds() + gfx::Vector2d(GetMirroredX(), y()) + parent_->CalculateOffsetToAncestorWithLayer(NULL));
        } else {
            SetLayerBounds(bounds_);
        }

        // In RTL mode, if our width has changed, our children's mirrored bounds
        // will have changed. Update the child's layer bounds, or if it is not a
        // layer, the bounds of any layers inside the child.
        if (base::i18n::IsRTL() && bounds_.width() != previous_bounds.width()) {
            for (int i = 0; i < child_count(); ++i) {
                View* child = child_at(i);
                child->UpdateChildLayerBounds(
                    gfx::Vector2d(child->GetMirroredX(), child->y()));
            }
        }
    } else {
        // If our bounds have changed, then any descendant layer bounds may have
        // changed. Update them accordingly.
        UpdateChildLayerBounds(CalculateOffsetToAncestorWithLayer(NULL));
    }

    OnBoundsChanged(previous_bounds);

    if (needs_layout_ || previous_bounds.size() != size()) {
        needs_layout_ = false;
        Layout();
    }

    if (GetNeedsNotificationWhenVisibleBoundsChange())
        OnVisibleBoundsChanged();

    // Notify interested Views that visible bounds within the root view may have
    // changed.
    if (descendants_to_notify_.get()) {
        for (Views::iterator i(descendants_to_notify_->begin());
             i != descendants_to_notify_->end(); ++i) {
            (*i)->OnVisibleBoundsChanged();
        }
    }
}

// static
void View::RegisterChildrenForVisibleBoundsNotification(View* view)
{
    if (view->GetNeedsNotificationWhenVisibleBoundsChange())
        view->RegisterForVisibleBoundsNotification();
    for (int i = 0; i < view->child_count(); ++i)
        RegisterChildrenForVisibleBoundsNotification(view->child_at(i));
}

// static
void View::UnregisterChildrenForVisibleBoundsNotification(View* view)
{
    if (view->GetNeedsNotificationWhenVisibleBoundsChange())
        view->UnregisterForVisibleBoundsNotification();
    for (int i = 0; i < view->child_count(); ++i)
        UnregisterChildrenForVisibleBoundsNotification(view->child_at(i));
}

void View::RegisterForVisibleBoundsNotification()
{
    if (registered_for_visible_bounds_notification_)
        return;

    registered_for_visible_bounds_notification_ = true;
    for (View* ancestor = parent_; ancestor; ancestor = ancestor->parent_)
        ancestor->AddDescendantToNotify(this);
}

void View::UnregisterForVisibleBoundsNotification()
{
    if (!registered_for_visible_bounds_notification_)
        return;

    registered_for_visible_bounds_notification_ = false;
    for (View* ancestor = parent_; ancestor; ancestor = ancestor->parent_)
        ancestor->RemoveDescendantToNotify(this);
}

void View::AddDescendantToNotify(View* view)
{
    DCHECK(view);
    if (!descendants_to_notify_.get())
        descendants_to_notify_.reset(new Views);
    descendants_to_notify_->push_back(view);
}

void View::RemoveDescendantToNotify(View* view)
{
    DCHECK(view && descendants_to_notify_.get());
    Views::iterator i(std::find(
        descendants_to_notify_->begin(), descendants_to_notify_->end(), view));
    DCHECK(i != descendants_to_notify_->end());
    descendants_to_notify_->erase(i);
    if (descendants_to_notify_->empty())
        descendants_to_notify_.reset();
}

void View::SetLayerBounds(const gfx::Rect& bounds)
{
    layer()->SetBounds(bounds);
    SnapLayerToPixelBoundary();
}

// Transformations -------------------------------------------------------------

bool View::GetTransformRelativeTo(const View* ancestor,
    gfx::Transform* transform) const
{
    const View* p = this;

    while (p && p != ancestor) {
        transform->ConcatTransform(p->GetTransform());
        gfx::Transform translation;
        translation.Translate(static_cast<float>(p->GetMirroredX()),
            static_cast<float>(p->y()));
        transform->ConcatTransform(translation);

        p = p->parent_;
    }

    return p == ancestor;
}

// Coordinate conversion -------------------------------------------------------

bool View::ConvertPointForAncestor(const View* ancestor,
    gfx::Point* point) const
{
    gfx::Transform trans;
    // TODO(sad): Have some way of caching the transformation results.
    bool result = GetTransformRelativeTo(ancestor, &trans);
    auto p = gfx::Point3F(gfx::PointF(*point));
    trans.TransformPoint(&p);
    *point = gfx::ToFlooredPoint(p.AsPointF());
    return result;
}

bool View::ConvertPointFromAncestor(const View* ancestor,
    gfx::Point* point) const
{
    gfx::Transform trans;
    bool result = GetTransformRelativeTo(ancestor, &trans);
    auto p = gfx::Point3F(gfx::PointF(*point));
    trans.TransformPointReverse(&p);
    *point = gfx::ToFlooredPoint(p.AsPointF());
    return result;
}

bool View::ConvertRectForAncestor(const View* ancestor,
    gfx::RectF* rect) const
{
    gfx::Transform trans;
    // TODO(sad): Have some way of caching the transformation results.
    bool result = GetTransformRelativeTo(ancestor, &trans);
    trans.TransformRect(rect);
    return result;
}

bool View::ConvertRectFromAncestor(const View* ancestor,
    gfx::RectF* rect) const
{
    gfx::Transform trans;
    bool result = GetTransformRelativeTo(ancestor, &trans);
    trans.TransformRectReverse(rect);
    return result;
}

// Accelerated painting --------------------------------------------------------

void View::CreateLayer()
{
    // A new layer is being created for the view. So all the layers of the
    // sub-tree can inherit the visibility of the corresponding view.
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->UpdateChildLayerVisibility(true);

    SetLayer(new ui::Layer());
    layer()->set_delegate(this);
#if !defined(NDEBUG)
    layer()->set_name(GetClassName());
#endif

    UpdateParentLayers();
    UpdateLayerVisibility();

    // The new layer needs to be ordered in the layer tree according
    // to the view tree. Children of this layer were added in order
    // in UpdateParentLayers().
    if (parent())
        parent()->ReorderLayers();

    Widget* widget = GetWidget();
    if (widget)
        widget->UpdateRootLayers();

    // Before having its own Layer, this View may have painted in to a Layer owned
    // by an ancestor View. Scheduling a paint on the parent View will erase this
    // View's painting effects on the ancestor View's Layer.
    // (See crbug.com/551492)
    SchedulePaintOnParent();
}

void View::UpdateParentLayers()
{
    // Attach all top-level un-parented layers.
    if (layer() && !layer()->parent()) {
        UpdateParentLayer();
    } else {
        for (int i = 0, count = child_count(); i < count; ++i)
            child_at(i)->UpdateParentLayers();
    }
}

void View::OrphanLayers()
{
    if (layer()) {
        if (layer()->parent())
            layer()->parent()->Remove(layer());

        // The layer belonging to this View has already been orphaned. It is not
        // necessary to orphan the child layers.
        return;
    }
    for (int i = 0, count = child_count(); i < count; ++i)
        child_at(i)->OrphanLayers();
}

void View::ReparentLayer(const gfx::Vector2d& offset, ui::Layer* parent_layer)
{
    layer()->SetBounds(GetLocalBounds() + offset);
    DCHECK_NE(layer(), parent_layer);
    if (parent_layer)
        parent_layer->Add(layer());
    layer()->SchedulePaint(GetLocalBounds());
    MoveLayerToParent(layer(), gfx::Point());
}

void View::DestroyLayer()
{
    ui::Layer* new_parent = layer()->parent();
    std::vector<ui::Layer*> children = layer()->children();
    for (size_t i = 0; i < children.size(); ++i) {
        layer()->Remove(children[i]);
        if (new_parent)
            new_parent->Add(children[i]);
    }

    LayerOwner::DestroyLayer();

    if (new_parent)
        ReorderLayers();

    UpdateChildLayerBounds(CalculateOffsetToAncestorWithLayer(NULL));

    SchedulePaint();

    Widget* widget = GetWidget();
    if (widget)
        widget->UpdateRootLayers();
}

// Input -----------------------------------------------------------------------

bool View::ProcessMousePressed(const ui::MouseEvent& event)
{
    int drag_operations = (enabled_ && event.IsOnlyLeftMouseButton() && HitTestPoint(event.location())) ? GetDragOperations(event.location()) : 0;
    ContextMenuController* context_menu_controller = event.IsRightMouseButton() ? context_menu_controller_ : 0;
    View::DragInfo* drag_info = GetDragInfo();

    // TODO(sky): for debugging 360238.
    int storage_id = 0;
    if (event.IsOnlyRightMouseButton() && context_menu_controller && kContextMenuOnMousePress && HitTestPoint(event.location())) {
        ViewStorage* view_storage = ViewStorage::GetInstance();
        storage_id = view_storage->CreateStorageID();
        view_storage->StoreView(storage_id, this);
    }

    const bool enabled = enabled_;
    const bool result = OnMousePressed(event);

    if (!enabled)
        return result;

    if (event.IsOnlyRightMouseButton() && context_menu_controller && kContextMenuOnMousePress) {
        // Assume that if there is a context menu controller we won't be deleted
        // from mouse pressed.
        gfx::Point location(event.location());
        if (HitTestPoint(location)) {
            if (storage_id != 0)
                CHECK_EQ(this, ViewStorage::GetInstance()->RetrieveView(storage_id));
            ConvertPointToScreen(this, &location);
            ShowContextMenu(location, ui::MENU_SOURCE_MOUSE);
            return true;
        }
    }

    // WARNING: we may have been deleted, don't use any View variables.
    if (drag_operations != ui::DragDropTypes::DRAG_NONE) {
        drag_info->PossibleDrag(event.location());
        return true;
    }
    return !!context_menu_controller || result;
}

bool View::ProcessMouseDragged(const ui::MouseEvent& event)
{
    // Copy the field, that way if we're deleted after drag and drop no harm is
    // done.
    ContextMenuController* context_menu_controller = context_menu_controller_;
    const bool possible_drag = GetDragInfo()->possible_drag;
    if (possible_drag && ExceededDragThreshold(GetDragInfo()->start_pt - event.location()) && (!drag_controller_ || drag_controller_->CanStartDragForView(this, GetDragInfo()->start_pt, event.location()))) {
        DoDrag(event, GetDragInfo()->start_pt,
            ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE);
    } else {
        if (OnMouseDragged(event))
            return true;
        // Fall through to return value based on context menu controller.
    }
    // WARNING: we may have been deleted.
    return (context_menu_controller != NULL) || possible_drag;
}

void View::ProcessMouseReleased(const ui::MouseEvent& event)
{
    if (!kContextMenuOnMousePress && context_menu_controller_ && event.IsOnlyRightMouseButton()) {
        // Assume that if there is a context menu controller we won't be deleted
        // from mouse released.
        gfx::Point location(event.location());
        OnMouseReleased(event);
        if (HitTestPoint(location)) {
            ConvertPointToScreen(this, &location);
            ShowContextMenu(location, ui::MENU_SOURCE_MOUSE);
        }
    } else {
        OnMouseReleased(event);
    }
    // WARNING: we may have been deleted.
}

// Accelerators ----------------------------------------------------------------

void View::RegisterPendingAccelerators()
{
    if (!accelerators_.get() || registered_accelerator_count_ == accelerators_->size()) {
        // No accelerators are waiting for registration.
        return;
    }

    if (!GetWidget()) {
        // The view is not yet attached to a widget, defer registration until then.
        return;
    }

    accelerator_focus_manager_ = GetFocusManager();
    if (!accelerator_focus_manager_) {
        // Some crash reports seem to show that we may get cases where we have no
        // focus manager (see bug #1291225).  This should never be the case, just
        // making sure we don't crash.
        NOTREACHED();
        return;
    }
    for (std::vector<ui::Accelerator>::const_iterator i(
             accelerators_->begin() + registered_accelerator_count_);
         i != accelerators_->end(); ++i) {
        accelerator_focus_manager_->RegisterAccelerator(
            *i, ui::AcceleratorManager::kNormalPriority, this);
    }
    registered_accelerator_count_ = accelerators_->size();
}

void View::UnregisterAccelerators(bool leave_data_intact)
{
    if (!accelerators_.get())
        return;

    if (GetWidget()) {
        if (accelerator_focus_manager_) {
            accelerator_focus_manager_->UnregisterAccelerators(this);
            accelerator_focus_manager_ = NULL;
        }
        if (!leave_data_intact) {
            accelerators_->clear();
            accelerators_.reset();
        }
        registered_accelerator_count_ = 0;
    }
}

// Focus -----------------------------------------------------------------------

void View::InitFocusSiblings(View* v, int index)
{
    int count = child_count();

    if (count == 0) {
        v->next_focusable_view_ = NULL;
        v->previous_focusable_view_ = NULL;
    } else {
        if (index == count) {
            // We are inserting at the end, but the end of the child list may not be
            // the last focusable element. Let's try to find an element with no next
            // focusable element to link to.
            View* last_focusable_view = NULL;
            for (Views::iterator i(children_.begin()); i != children_.end(); ++i) {
                if (!(*i)->next_focusable_view_) {
                    last_focusable_view = *i;
                    break;
                }
            }
            if (last_focusable_view == NULL) {
                // Hum... there is a cycle in the focus list. Let's just insert ourself
                // after the last child.
                View* prev = children_[index - 1];
                v->previous_focusable_view_ = prev;
                v->next_focusable_view_ = prev->next_focusable_view_;
                prev->next_focusable_view_->previous_focusable_view_ = v;
                prev->next_focusable_view_ = v;
            } else {
                last_focusable_view->next_focusable_view_ = v;
                v->next_focusable_view_ = NULL;
                v->previous_focusable_view_ = last_focusable_view;
            }
        } else {
            View* prev = children_[index]->GetPreviousFocusableView();
            v->previous_focusable_view_ = prev;
            v->next_focusable_view_ = children_[index];
            if (prev)
                prev->next_focusable_view_ = v;
            children_[index]->previous_focusable_view_ = v;
        }
    }
}

void View::AdvanceFocusIfNecessary()
{
    // Focus should only be advanced if this is the focused view and has become
    // unfocusable. If the view is still focusable or is not focused, we can
    // return early avoiding furthur unnecessary checks. Focusability check is
    // performed first as it tends to be faster.
    if (IsAccessibilityFocusable() || !HasFocus())
        return;

    FocusManager* focus_manager = GetFocusManager();
    if (focus_manager)
        focus_manager->AdvanceFocusIfNecessary();
}

// System events ---------------------------------------------------------------

void View::PropagateThemeChanged()
{
    for (int i = child_count() - 1; i >= 0; --i)
        child_at(i)->PropagateThemeChanged();
    OnThemeChanged();
}

void View::PropagateLocaleChanged()
{
    for (int i = child_count() - 1; i >= 0; --i)
        child_at(i)->PropagateLocaleChanged();
    OnLocaleChanged();
}

void View::PropagateDeviceScaleFactorChanged(float device_scale_factor)
{
    for (int i = child_count() - 1; i >= 0; --i)
        child_at(i)->PropagateDeviceScaleFactorChanged(device_scale_factor);

    // If the view is drawing to the layer, OnDeviceScaleFactorChanged() is called
    // through LayerDelegate callback.
    if (!layer())
        OnDeviceScaleFactorChanged(device_scale_factor);
}

// Tooltips --------------------------------------------------------------------

void View::UpdateTooltip()
{
    Widget* widget = GetWidget();
    // TODO(beng): The TooltipManager NULL check can be removed when we
    //             consolidate Init() methods and make views_unittests Init() all
    //             Widgets that it uses.
    if (widget && widget->GetTooltipManager())
        widget->GetTooltipManager()->UpdateTooltip();
}

// Drag and drop ---------------------------------------------------------------

bool View::DoDrag(const ui::LocatedEvent& event,
    const gfx::Point& press_pt,
    ui::DragDropTypes::DragEventSource source)
{
    int drag_operations = GetDragOperations(press_pt);
    if (drag_operations == ui::DragDropTypes::DRAG_NONE)
        return false;

    Widget* widget = GetWidget();
    // We should only start a drag from an event, implying we have a widget.
    DCHECK(widget);

    // Don't attempt to start a drag while in the process of dragging. This is
    // especially important on X where we can get multiple mouse move events when
    // we start the drag.
    if (widget->dragged_view())
        return false;

    OSExchangeData data;
    WriteDragData(press_pt, &data);

    // Message the RootView to do the drag and drop. That way if we're removed
    // the RootView can detect it and avoid calling us back.
    gfx::Point widget_location(event.location());
    ConvertPointToWidget(this, &widget_location);
    widget->RunShellDrag(this, data, widget_location, drag_operations, source);
    // WARNING: we may have been deleted.
    return true;
}

} // namespace views
